September 19
Saint Januarius is invoked as patron of volcanic eruptions. Saint Januarius (Italian: San Gennaro) is honored as Bishop of Benevento and martyr under the Diocletian persecution. The earliest sources, the fifth-century Bobbio Missal and the sixth-century inscription in the Naples catacombs, attest his cultus from the early centuries. Sources: https://www.vatican.va/content/francesco/en/speeches/2015/march/documents/papa-francesco_20150321_napoli-pompei-clero.html.